Geophysical surveys are often used for oil and gas exploration in geophysical formations, which may be located below marine environments. Various types of signal sources and sensors may be used in different types of geophysical surveys. For example, electromagnetic (EM) surveys may be conducted using EM signals transmitted by an EM source and detected by EM sensors. Thus, for example, an EM source may create an electric field and the EM sensors may measure an induced electric field in a geophysical formation. Measured EM data may be used to determine where mineral reservoirs may be located in the geophysical formation. As another example survey type, seismic geophysical surveys are based on the use of acoustic waves. In such a survey, a vessel may tow an acoustic source (e.g., an air gun or a marine vibrator) and a plurality of streamers along which a number of acoustic sensors (e.g., hydrophones or geophones) are located. Acoustic waves generated by the source may then be transmitted to the earth's crust and then reflected back and captured at the sensors. Acoustic waves received during a marine seismic survey may be analyzed to locate hydrocarbon-bearing geological structures, and thus determine where deposits of oil and natural gas may be located.
Geophysical survey data may be taken in a plurality of dimensions, including different shot points (e.g., of an array sensors relative to a source) and source frequencies, for example. Further, models of geophysical strata may include various model parameters such as conductivity, porosity, saturation, etc. Interpreting seismic data may include forward modeling which may involve selecting a set of model parameters and solving a system of equations with the selected model parameters using obtained geophysical data. Inverse modeling may involve solving similar systems of equations using different model parameters to determine which model parameters best match the geophysical data. Thus, in inverse modeling, the model parameters may be considered an additional dimension to the modeling problem.
Solving systems of equations may be computationally intensive, especially for inverse modeling problems.
This specification includes references to “one embodiment” or “an embodiment.” The appearances of the phrases “in one embodiment” or “in an embodiment” do not necessarily refer to the same embodiment. Particular features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure.
Various units, circuits, or other components may be described or claimed as “configured to” perform a task or tasks. In such contexts, “configured to” is used to connote structure by indicating that the units/circuits/components include structure (e.g., circuitry) that performs the task or tasks during operation. As such, the unit/circuit/component can be said to be configured to perform the task even when the specified unit/circuit/component is not currently operational (e.g., is not on). The units/circuits/components used with the “configured to” language include hardware—for example, circuits, memory storing program instructions executable to implement the operation, etc. Reciting that a unit/circuit/component is “configured to” perform one or more tasks is expressly intended not to invoke 35 U.S.C. §112(f) for that unit/circuit/component.
It is to be understood the present disclosure is not limited to particular devices or methods, which may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used herein, the singular forms “a”, “an”, and “the” include singular and plural referents unless the content clearly dictates otherwise. Furthermore, the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not in a mandatory sense (i.e., must). The term “include,” and derivations thereof, mean “including, but not limited to.” The term “coupled” means directly or indirectly connected.